Counterbalancing stair or ladder for fire-escapes



No. 752,(132.. PATBNTED 123.16, 1904.

I. L. LARSON.

GOUNTERBALANCING STAIR. 0R LADDER FR FIRE SCAPES. FP LIOATIoN FILED MAE. 5. 1902.

' im MODL.

- ancing Stair or Ladder for Fire-Escapes, of

Whichthe following is a. specification.

. and

ings, 1n `Winch-- l stairor ladder, illustrating the vimproved device, the dotted linesshowing the Y position assumed by .the device under an an- 'for mounting, with one/end in the Wall of a `sion-arm 16 is fixed to the pivoted end of' the tension-arm 16 preferably is in longitudinal '14 and theextension-arm. The

only of the side bars of the ladder orstair i `has the effect of permitting a twist or Wind .'Navsaoea. Y

` y'UNITED STATES rammed February 1e, 1904,

PATENT OFFICE.

'PETER L. Lassen, or Dasl Monins, iowa.

COUNTERBALANCING. STAIR on LADDER Foa FIRE-ESCAPES. A

sPEcIFIcA'rIoN formingpae of Letters Patent Approach and nach s, i902.

.To all whom it 11mg/ wry/cem: l

.Be it known that I, PETER L. LAnsoN, a citizen ofthe United States of America, and 'a resident of Des Moines, Polk 'countyIoWa, have invented 'a new and useful Counter-bal- Figure 1 is a side elevation illustrating my Fig. improved meansl ern-:- loyed to sustain the alinement of the ladderaIS. v I

In the construction of the device, as shown, I the numeral-10 designates a pivot-rod arranged gular adjustment of the stair-or ladder. 2 is a topiview of one form of my building and the oppositeend braced bybrackets v11 1'2 to said Wall.

A ladder or stair is provided composed of side bars`13 14:, connected by steps or rungs 15 in any ordinary and desirable manner. The side bars 13 14 of the stair or ladder are pivotally connected at on'e end tofvthe pivot-rod v10, and an extenside bar 14 and extends `therefrom in an opposite directionfrom the pivot-rod. The exalinement with the side bar 14. Y The weight of the extension-arm 16 approximates closely to the weight of the ladder or stair, and a truss-rod 17 is xed at its ends to the opposite extremities, respectively, of the side bar applicationor connection ofthe extension-arm 16 to one of said in respect of a drooping ofthe inclinedposition.

No. |752,082, dated February 16, 1994. Serial Nol 96,759. (No model.)

` free end of the side bar 13. To-overcome such drooping of the'iiree end of the side bar 13, I mount a steel 'rod 18v with one angular end fixed against rotation in a bracket 19 0n one round or step of the ladder adjacent the pivot-rod 10, and the other angular end of said-rod is passed through an angular seat in a bracket 20,'xed `to one round or step of the ladder adjacent the free end thereof. The steel rod 18 is twisted yrelative to its longitudinal center' in the direction in which the stair or ladder tends to twist or wind prior to the securancel of the bracket 20 to the step or rung 'and then the torsional resilience or twist of' the'rod 18 tends to neutralize, overcome,

and compensate for the normal twist of the ladder o'r stair and preserve the alinement andl parallel'positioning of the side bar. 13 relative to the side bar 14:. A hanger 21 is mount- I ed on' and embraces the truss-rod 17, and a disk Weight 22 is mounted on and supported vby said hanger and depends between the trussrod and the inner end of the extension-arm 16; The hanger 21 is adjustable longitudinally of the truss-rod 17 within thelimits of the space. between the .struts 23 24;, supporting said truss-romand said hanger lmay be locked in any given position by means of keys 25, Wedges, or other desired fastenings, whereby itis connected to the truss-rod. A When the stairi's in a horizontal position,

as shown by solid linesl in Fig. 1', `the hanger is attached to the truss-rod 17 at a point in the rear of and above the pivot-rod 10, and the weight of the disk 22 is 'such that it effectually holds the ladder or stair in such horizontal position.` `The length of the struts 23 24 is such that when the free end of the, lad-v deror stair is drawn downward, as illustrated by dotted lines in ldig.,1,theweight-disk,may`

swing forward across the axis cfa/the pivotrod 10 and overcome the equilibrium of the vstair in the end of holding said stair in'such of positions of the weight-disk 22 said Weightdisk will hold the ladder orstair in -eithea horizontal or radically-inclined position. Normally the ladder or stair wouldbehori- 'zontal at an altitude ontlof the reach of a per- By reason of the change yson on the ground. Aperson could approach the upper end of the ladder` or stair from a Window or other opening in the wall of a building and tilt said ladder or stair by an apmade in order that the counterbalancingv Weight may neutralize the effect of accumulations of ice and snow `which' may adhere to the ladderV or stair on one side of the pivot in excessof the amount adhering to the extension-arm and truss-rod on the opposite side of the pivot.v A stop-rod 26 is' mounted in and projects horizontally from the Wall of the building and serves as a rest to limit the downward movement of ,the extension-arm 16 and maintain the horizontal positioning of the stair or ladder and extension-arm against the 'gravity of the disk 22. The disk 22 and hanger. 21 may be, adjusted along the trussrod 17 for' the purpose of determining the amount of force necessary to oscillat'e the ladder or stair and to regulate the stability with Which said Weight Will maintain either posi- The Weight-.

tioning of the stair or ladder at the extremities of its movement.

I claim as my invention- 1. The counterbalancing-stair for {ire-escapes, comprising the stair lpivoted to a suitable support, an vextension-arm on said stair, a truss-rod connecting said extension-arm and stair and a counterbalancing-Weight suspended on said truss-rod and arranged 'to swing across the axis of pivoting of the stair.

2. The combi-nation of the stair, the twisted spring-rod 18 longitudinally of and below the central portion of said stair and fixed at its ends thereto, the extension-arm on said stair, the truss-rod connecting the extremities of the stair and extension-rod, the pivot-rod on which said stair is pivotally mounted and the counterbalancing-Weight suspended on said truss-rod and arranged to swing across the axis of the pivot-rod in an angular adjustment of said stair-, 4

3. The combination of the stair pivotally mounted and arranged for angular adjustment,

a truss-rod on said stair and aicounterbalancing-weight suspended from said truss-rod and `arranged to swing across the axis of pivoting or' the stair. f

Signed by'me' at Des Moines, Iowa, this 23d day of January, 1902. v J

' PETER L. LARSON. Witnesses S. C. SWEET, T. A. YOUNGBERG. 

